A combative Mr. Skilling took issue with Ms. Watkins' testimony, and denied her previous testimony that he fooled Enron's former chairman, Kenneth Lay about the company's financial health.

"First, I have not lied to Congress or anyone else about my recollection while I was at Enron. Second, I never duped Ken Lay. I heard Ms. Watkins testify to her opinion. I have no idea what the basis is for her opinion," he said.

Mr. Skilling said he saw no reason to be concerned by Enron's partnerships because the company's auditors signed off on them.

Ms. Watkins and current Enron President Jeff McMahon testified that they had raised questions within the company about the accounting practices that led to the bankruptcy.

Besides Congress, the Justice Department and the Security and Exchange Commission are also investigating Enron's collapse.